diff --git a/README.md b/README.md
index c962cf0..abf6ff4 100644
--- a/README.md
+++ b/README.md
@@ -16,11 +16,10 @@ Initially DirectX 12 backend was an exercise to learn this graphics API. It turn
 #### New cvars:
 * **r_renderAPI** - 3D API to use: 0 - OpenGL, 1 - Vulkan, 2 - DX12. Requires vid_restart.
 
-* **r_twinMode** - Debug feature to compare rendering output between OpenGL/Vulkan/DX12 APIs.
-    If enabled, renderer uses multiple APIs and renders current frame to two or three side-by-side windows. Requires vid_restart.
+* **r_twinMode** - Debug feature to compare rendering output between OpenGL/Vulkan/DX12 APIs. Requires vid_restart.
+  * r_twinMode=1 : one additional window is created. If the main window uses graphics API defined by r_renderAPI then the additional window will use graphics API with index (r_renderAPI+1)%3
+  * r_twinMode=2 : two additional windows are created and all 3 graphics APIs are active simultaneously.
 
-*r_twinMode* is a bitmask. The following values can be combined to enable additional graphics backends: 1 - OpenGL, 2 - Vulkan, 4 - DX12. For example: r_twinMode=7 (1+2+4) - enables all backends and renders to 3 windows. r_twinMode=1 - enables Vulkan backend in addition to active backend defined by *r_renderAPI*.  
-    
 #### Additional information:
 * Q: How to start game with vulkan support? A: `quake3-ke.exe +set r_renderAPI 1`.
 * Q: How to enable vulkan support from Q3 console? A: `\r_renderAPI 1` then `\vid_restart`.
diff --git a/src/engine/platform/win_glimp.c b/src/engine/platform/win_glimp.c
index 58f5b69..6d120e6 100644
--- a/src/engine/platform/win_glimp.c
+++ b/src/engine/platform/win_glimp.c
@@ -494,9 +494,7 @@ static HWND create_twin_window(int width, int height, RenderApi render_api)
     cvar_t* vid_ypos = ri.Cvar_Get ("vid_ypos", "", 0);
 	int x, y;
 
-	bool show_three_windows = (r_twinMode->integer | (1 << get_render_api())) == 7;
-
-	if (!show_three_windows) { // two windows
+	if (r_twinMode->integer == 1) { // two windows
 		x = vid_xpos->integer + width + 5; // offset to the right of the main window
 		y = vid_ypos->integer;
 	} else { // three windows
diff --git a/src/engine/renderer/tr_init.c b/src/engine/renderer/tr_init.c
index d67e900..dfb8b9e 100644
--- a/src/engine/renderer/tr_init.c
+++ b/src/engine/renderer/tr_init.c
@@ -211,7 +211,10 @@ static void InitRenderAPI( void )
 #endif
 
 		// OpenGL
-		if (get_render_api() == RENDER_API_GL || (r_twinMode->integer&1)) {
+		if (get_render_api() == RENDER_API_GL ||
+			r_twinMode->integer == 1 && get_render_api() == RENDER_API_DX ||
+			r_twinMode->integer == 2)
+		{
 			GLimp_Init();
 
 			GLint temp;
@@ -222,14 +225,20 @@ static void InitRenderAPI( void )
 		}
 
 		// VULKAN
-		if (get_render_api() == RENDER_API_VK || (r_twinMode->integer&2)) {
+		if (get_render_api() == RENDER_API_VK ||
+			r_twinMode->integer == 1 && get_render_api() == RENDER_API_GL ||
+			r_twinMode->integer == 2)
+		{
 			vk_imp_init();
 			vk_initialize();
 		}
 
 		// DX12
 #ifndef DISABLE_DX12
-		if (get_render_api() == RENDER_API_DX || (r_twinMode->integer&4)) {
+		if (get_render_api() == RENDER_API_DX ||
+			r_twinMode->integer == 1 && get_render_api() == RENDER_API_VK ||
+			r_twinMode->integer == 2)
+		{
 			dx_imp_init();
 			dx_initialize();
 		}
diff --git a/src/engine/renderer/tr_local.h b/src/engine/renderer/tr_local.h
index ead6f61..69254fc 100644
--- a/src/engine/renderer/tr_local.h
+++ b/src/engine/renderer/tr_local.h
@@ -958,14 +958,12 @@ RenderApi get_render_api();
 //
 extern cvar_t	*r_renderAPI;			// 3D API to use: 0 - OpenGL, 1 - Vulkan, 2 - DX12
 
-extern cvar_t	*r_twinMode;			// Allows to render the same frame in different windows using different graphics APIs.
-										// This cvar specifies a bitmask that determines which APIs.
-										// 0 - regular rendering with single window using the graphics API specified by r_renderAPI.
-										// bit 0 - enables OpenGL backend
-										// bit 1 - enables Vulkan backend
-										// bit 2 - enables DX12 backend
-										// Combinations of the above values are allowed, for example, r_twinMode=7 creates three diffent
-										// windows using all the supported APIs.
+extern cvar_t	*r_twinMode;			// Debug feature to compare rendering output between OpenGL/Vulkan/DX12 APIs.
+										// Possible values:
+										//		r_twinMode=1 : one additional window is created. If the main window uses graphics API
+										//		defined by r_renderAPI then the additional window will use graphics API with index (r_renderAPI+1)%3
+										//
+										//		r_twinMode=2 : two additional windows are created and all 3 graphics APIs are active simultaneously.
 
 extern cvar_t	*r_railWidth;
 extern cvar_t	*r_railCoreWidth;